ESTABLISHMENT AND CHARACTERIZATION OF AN IMMORTAL MACROPHAGE-LIKE CELL-LINE INDUCIBLE TO DIFFERENTIATE TO OSTEOCLASTS

Osteoclasts are hematopoietic cells essential for bone remodeling and resorption. To understand the process of osteoclast development, we es tablished a macrophage-like cell line C7 that has the potential to dif ferentiate into functional osteoclasts; multinuclear tartrate-resistan t acid phosphatase positive cells capable of forming pits on dentin sl ices, C7 cells share the characteristics of their cell surface molecul es and phagocytic activity with macrophages, Generation of osteoclasts from C7 cells was mostly suppressed by the addition of a function-blo cking antibody directed to c-Fms, the receptor for macrophage-colony s timulating factor (M-CSF), or by osteoclastogenesis inhibitory factor (OCIF), These responses correspond well with the osteoclast precursors present in bone marrow and peritoneal cavity, Reagents such as bacter ial lipopolysaccharide and granulocyte/macrophage-CSF that are known t o act as inducers for other cell lineages rather than osteoclasts abol ished the potential of osteoclastogenesis in C7 cells, These phenotype s of C7 cells have been stably maintained for more than 2 years, We be lieve that the cell line established in this study will provide an imp ortant tool for osteoclast biology. (C) 1998 Academic Press.